The digital computer is so commonly used as a programmable computer because the size and the capacity of digital memory components have rapidly become small and large, respectively, in comparison to analog memories. But recently, it is close to the limit to produce higher density of digital LSI. Conventionally, the scale of a memory circuit is large and the process of production is complicated in order to realize a memory in an analog or in a multilevel architecture.
A method for downsizing a block of memory cell storing analog data by means of the circulation of data on a plural number of linear CCD arrays in order to solve the aforementioned problem has been developed; however, this method is problematic because data is worse when the CCD circulation speed is slower, and electric power consumption necessarily increases when the circulation speed is increased to prevent the data from getting worse and to facilitate accessing the circulating data at a high speed.